Nonchanneling tobacco smoke filament filter



March 20, 1962 P. 1.. COBB, JR

NONCHANNELING TOBACCO SMOKE FILAIVIENT FILTER Filed July 2, 1959 igzl OVER ENTIRE INTERIOR OF WRAP we mm EN 0 2 PAPER WRAP FILRMENT BONDED 7 TO PAPER WRAP M E I wwwmw mw mw H H F vm A o PharaLee GoblgJn INVENTOR.

.A'I' TORNE Y5 Uited States of New Jersey Filed July 2, 1959, Ser. No. 824,577 14 Claims. (Cl. 131-208) This invention relates to a tobacco smoke filter. More particularly, this invention relates to a tobacco smoke filter prepared from crimped, continuous cellulose acetate filaments enclosed in a paper wrapper or other similar ribbon form of wrapper wherein any by-passing between the wrapper and the filaments forming the filter is obviated or minimized.

At the present time in industry a substantial number of the tobacco smoke filters are manufactured from crimped, continuous filaments wherein the filaments are compacted into an elongated rod form which is wrapped around its circumference with a web type of wrapping material such as a paper wrapper. A glue is applied on the seam where the wrapper comes together and overlaps in order to enclose the filter. Normal expansion of the crimped filaments has been relied upon in most instances to keep the filaments, in the form of a rod, from falling out of the wrapper.

In companion copending applications of which I am an inventor, namely application Serial No. 324,284 and 762,382, of which the present application is a continuation-in-part, there is described a tobacco smoke filter wherein the outer portion of the filter is comprised of a fused continuous sheath, Which sheath is also joined to the core filaments through which core filaments the filtering takes place. One of the advantages of such sheath type of filter as described in said companion copending atent is sensitive to the solvent action of the plasticizer and (3) a water soluble adhesive. With a filter plug wrap paper coated with a thermoplastic compound comprising principally polyetyhlene, the paper is heated to the tacky point of the coating as it is fed into the machine, by means of strip heaters and/or infrared bulbs. The garniture trumpet may be heated also to impart some heat to the applications is that substantially no or only a small amount of by-passing can take place between the outer sheath means and the inner or core component.

Accordingly, it is believed apparent that it would be a highly desirable result to improve the currently used paper-wrapped type of filter in a manner which will elimi nate or minimize the by-passing that may now take place between the paper wrapper and the filaments contained in the wrapper. After extended investigation, I have found certain relatively simple and practical ways in which the paperwrapped type of filter may be materially improved not only from the standpoint of efiiciency of filter action, but also from the standpoint of physical stability as will be apparent from the description which follows.

This invention has for an object to provide a non-bypassing ribbon-wrapped filament filter, particularly a paper-wrapped filter. Another object is to provide an improved paper-wrapped filter wherein not only is the filtration efiiciency improved, but also the physical stability of the filter is improved. Still another object is to provide a simple but practical method of making improved wrapped type of filters of the class indicated. Other objects will appear herein-after.

In the broader aspects, my invention involves the use of a plug (filament-filter) wrap paper coated with an adhesive by means of which the outer layer of filaments in the filter elements are made to adhere to the wrapping material. By thus fixing the position of the filaments at the periphery of the filter, the shrinkage associated with smoking, particularly with fine denier per filament tows, is eliminated. As a result, the smoke must pass through the filter between the filaments and the tar removal is increased and more consistent.

Any one of several general types of adhesives may be used: (1) a thermoplastic material,(2) a compound which tow itself. As a plasticizer-soluble adhesive, a compound composed of a mixture of cellulose acetate and plasticizer therefor may be used. The coated paper is fed into the plug maker and the seam is made with heat sealing. An additional advantage of this compound, and of the thermoplastic compound, is the fact that under normal conditions no additional adhesive application is necessary to effect the sealing of the wrapper seam. This significantly simplifies that portion of the filter plug manufacturing procedure. With a paper coated with a water-soluble adhesive, the adhesive is activated by the application of water from a sponge or wicking device just before the paper enters the garniture. Here also, the application of additional adhesive for the seam line is unnecessary. The heated sealer sets the adhesive at the seam line quickly, While the adhesive on the remainder of the paper although setting more slowly, will set firmly for bonding the filaments to the paper.

Inasmuch as the apparatus used to carry out the present invention may be generally the same as shown in Crawford and Stevens Patent No. 2,794,480, with the additional heating elements and the like referred to above, added reference may be made to this patent and further description of apparatus does not appear to be needed.

However, for a better understanding of the novel nonby-passing filament filter of the present invention, reference may be made to the attached drawing forming a part of the present application.

In the drawing:

FIG. 1 is a semidigrammatic perspective View of an opened up segment of a filter rod in accordance with the present invention; and

FIG. 2 is a sectional view on a somewhat slightly enlaraed scale of a filter rod in accordance with the present invention.

Referring to FIG. 1, 2 represents the paper wrapper which may be the same general type of paper that has heretofore been used for wrapping filters. However, in accordance with the present invention, at least the inner surface of this paper Wrapper is substantially completely coated as at 3 with certain types of coatings as mentioned above and as will be described in further detail hereinafter. The crimped continuous filaments making up the filter are shown at 4.

In making my new filter, although FIG. 1 shows the wrapper in an opened up condition, in the finished filter the wrapper would firmly encircle the filaments.

Referring to FIG. 2, it will be observed that due to the coating 3 which as just mentioned substantially continuously covers the entire inner surface of the wrapper, the wrapper may be very readily sealed at 6 where the wrapper overlaps when encircled about the filaments 4. Due to the heating or other action generally referred to above and which will be described in greater detail below, the various filaments as at 7 are bonded to the paper or other web wrapper 2 in a manner whereby any by-passing of the smoke between the wrapper and the filaments is simply and effectively obviated or minimized. In addition to this bonding of the filaments to the paper, the filter element is rendered more stable and firm.

In the following examples are described several embodiments of my invention. These are illustrations of the invention and should not be construed to unduly limit the invention.

Example I A 2.1 denier per filament, 46,000 total denier, regular cross-section, 16 crimps per inch (c.p.i.) tow was wrapped in plug wrap paper which had previously been coated on one side with a 0.0005" coating of 85% Epolene C low melting polyethylene and Piccolyte S-115L (a polyterpene resin added to improve the heat sealing by reduction of the melting point). The paper was heated with two strip heaters and an infrared lamp just before it entered the forming garniture of an apparatus as in Patent No. 2,794,480 and came in contact with the tow. The garniture trumpet was also heated so as to heat the tow while it was being condensed. The polyethylene coating heat-sealed to form the seam where the paper wrapped around the the filter and contacted itself. No other bonding agent was used. The filaments were sealed to the coating of the paper all the way around by the polyethylene compound. The smoke could not by-pass in this filter.

Example 11 A 2.1 denier per filament, 46,000 total denier, regular cross-section, l6 c.p.i. tow with 15.7 parts per hundred triacetin sprayed on the bloomed tow was wrapped in paper of pounds weight coated with a 0.0003" thick coating of a mixture of cellulose acetate and triacetin. The paper had previously been rod coated with a lacquer of the following formula:

, Percent Cellulose ace 15.0 Acetone 30.0 Triacetin 7.5 Ethyl acetate 47.5

Example III A 1.8 denier per filament, 41,000 total denier, regular cross-section, 20 c.p.i. tow was wrapped in a paper of 40 pound weight entirely coated on one side of the paper with a water-soluble animal glue. A sponge wick, wet with water, was applied to the coated side of the paper just before it went into the garniture. The water-activated coating formed the seam seal, and, after a two hour curing time, the filaments of the filter rod were firmly attached to the paper all the way around the filter by the glue.

While in the foregoing examples the Wrapper has been comprised of paper, other ribbon materials such as plastic sheeting may be used. For example, certain plastic sheeting has the advantage over paper of exhibiting less tendency to pull away from the filaments contained therein. The use of a plastic wrapper will be illustrated by the following:

Example IV then exposed to a moderate heat to cause surface solvation of the filaments and the sheet which resulted in the mutual bonding of the filaments and the acetate wrapper at points of contact.

Example V Filtering elements were prepared in the same manner as in Example IV consisting of a cellulose acetate tow of approximately 1,400 filaments of 35 denier per filament enclosed in a wrapper of acetate sheet .0015 inch thick and 28 mm. wide.

In all of the above examples tests of the new filter wherein the filaments were bonded to the web wrapper showed that the filter was considerably more eflicient. This increase in efficiency can be readily illustrated by the following:

A filter rod prepared from a 2.1 denier per filament, 46,000 total denier tow, using a conventional uncoated plug wrap with one line of adhesive on the paper other than at the lap, was subjected to the standard smoking test for the determination of tar removal efficiency. Its removal efficiency was found to be 20%, and visual examination disclosed severe leakage of the smoke between the periphery of the filter material and the plug wrap paper. A similar tow was fabricated into a filter rod but using a coated filter wrap such as described above, and specifically in accordance with Example I. Upon testing, the filter of this invention was found to have a tar removal efiiciency of 39% and no visual evidence of smoke leakage.

Thermoplastic adhesives other than polyethylene compounds may be used, such as polypropylene, polyvinyl acetates, copolymers of various acrylates and methacrylates, ethyl cellulose derivatives, various resins of the terpene family, and other thermoplastic materials known to those skilled in the art. However, it is generally desirable to lower the softening point of these compounds to a reasonable extent in order to reduce the amount of heat necessary to soften the coating. In regard to plasticizer-soluble adhesive coatings, the range of compounds which may be used is quite broad. It should be mentioned, however, that with cellulose acetate coatings or other materials with relatively high melting points it may be desirable to apply triacetin or some other solvent at the glue-line applicator in order to effect a rapid and firm seal of the lap. The limitations of water-soluble adhesives which must be considered are taste and toxicity. An adhesive which gives a good firm bond and is tasteless and non-toxic would be applicable within the framework of this invention. However, in many instances the non-water soluble bonding agents as in Example I are preferred. It is found that as the filament denier is lowered and, as a result, the filament stiffness diminishes, the necessity for some embodiment of this invention increases. Consequently, its use is of even greater advantage when tows of 1.3 denier per filament or less are used.

While as described above I have found that a very good coating may be prepared from low melting point polyethylene which contains a resin such as a polyterpene resin, there are several other hydrocarbon type coating compositions which may be used illustrated by the following: polypropylene, polyvinyl acetates, copolymers of various acrylates and methacrylates, ethyl cellulose derivatives, various resins of the terpene family and other thermoplastic materials known to those skilled in the art.

Likewise, while I prefer in particular the coating composition of cellulose ester containing triacetin plasticizer, since this is quite comparable and compatible with the cellulose acetate filaments making up the filter, there are certain other combinations of cellulose ester or the like and plasticizers which may be utilized exemplified by the following: cellulose acetate propionate, ethyl cellulose derivatives, polyvinyl acetates, copolymers of various acrylates and methacrylates, and others known to those skilled in the art for which triethyl citrate, methyl phthalyl ethyl glycollate, dimethoxyethyl, phthalate and tripropionin, or mixtures of two or more of these, are examples of suitable plasticizers.

In general, I prefer to use the same plasticizer in the coating composition as is used in plasticizing the continuous crimped filaments making up the filter.

There are also several other combinations which may be utilized with particular advantage. For example, when the continuous crimped filaments of the present invention are treated with a solution of sucrose octa-isobutyrate and plasticizer such as triacetin plasticizer, the utilization of a wrapper coated on its inner surface with a polyolefin coating as described in Example I above not only will serve to produce the non-by-passing type of filter, but prevents any external crystallization of the sucrose octa-isobutyrate on the outside of the filter element. In addition, when the compositions applied to the filaments contain powdered additives such as carbon particles, the wrapping material with the inner coating prevents the wrapping material from taking up the bonding medium which is for bonding the additive to the filaments. Therefore, the present invention provides a means of improving the manufacture of additive filters.

The use of the wrapper coated on the inner surface as described above also is advantageous for wrapping filament filters Where there is a small amount of bonding medium or no bonding medium used for causing internal bonding of the filaments, and hence the core filaments are only slightly bonded or not bonded at all. That is, the bonding of the filaments on the periphery of the filament core to the wrapper will impart some useful firmness to the resultant filter rod.

The preferred thermoplastic cellulose ester coating which I would use in many instances would be comprised of cellulose acetate containing to 30% plasticizer. The preferred plasticizer is triacetin although other plasticizers such as triethyl citrate, methyl phthalyl ethyl glycollate, dimethoxyethyl phthalate, and tripropionin may be used. In general, I apply my coatings to a wrapping paper which is of about 0.0010 to 0.0016 inch in thickness and is currently manufactured and sold as a conventional wrapping paper for filter plugs. However, as indicated above, in a number of instances my invention may be improved by using a heavier plug wrapper paper such as, for example, a paper of a thickness of 0.0017 to 0.0050 inch. When using this heavier ribbon wrap, the same type of coatings already extensively discussed above would be applied to the interior surface thereof.

There are several further changes which may be made in my invention with added advantages. For example, the coating compositions applied to the wrap may have incorporated therein any one or more of various non-toxic, odor-free coloring agents such as FD & C Citrus Red #2, Brilliant Blue FCF, Acid Violet 6B or any of the other food, drug and cosmetic dyes sanctioned by the Food and Drug Administration. Such coloring agents in the adhesive on the inner surface of the wrap will show through the wrap thereby giving an effect of a tinted paper when viewed from the outside of the filter. Or certain flavoring agents such as menthol, oil of wintergreen, oil of cloves, and similar essential oils as well as other food-approved flavoring agents may be incorporated in the coating composition for imparting a pleasing taste to the filter.

The invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention as described hereinabove and as defined in the appended claims.

I claim:

1. A non-by-passing tobacco smoke filter comprised of a core section made up of crirnped, continues thermoplastic filaments joined at random points of contact, a paper wrapping material around the periphery of the core, the filter being characterized in that the wrapper carries on a substantial portion of the surface adjacent the core a heat-sensitive coating composition which is bonded to a substantial portion of the periphery core filaments whereby any tendency of smoke passed through the filter to by-pass between the wrapper and the core filaments is thereby minimized.

2. A filter in accordance with claim 1 wherein the coating is to a substantial extent comprised of a polyolefin which will bond to the periphery filaments.

3. A filter in accordance with claim 1 wherein the denier per filament is less than 3 and the bonding of the periphery filaments to the wrapper imparts stiffness to the filter element.

4. A filter in accordance with claim 1 wherein the filaments are plasticized and the wrapper is coated with a composition which is substantially composed of a compound plasticized by the plasticizer on the filaments, said plasticizer being selected from the group consisting of triacetin, ethyl acetate, and dimethoxyethyl phthalate.

5. A filter in accordance with claim 1 wherein the wrapper is coated with a composition which is substantially a cellulose ester.

6. A tobacco smoke filter comprised of a core section made up of filaments, a paper wrapper around the periphery of the core filaments, the inner surface of said paper wrapper adjacent the periphery core filaments being bonded to said filaments at random points of contact whereby any tendency of smoke passed through the filter to by-pass between the paper wrapper and core filaments is minimized.

7. A filter in accordance with claim 6 wherein the inner surface of the paper wrapper adjacent the periphery core filaments is bonded to said filaments at random points of contact by a composition which is a plasticized cellulose ester.

8. A filter in accordance with claim 6 wherein the plasticized cellulose ester comprises cellulose acetate and triacetin.

9. A tobacco smoke filter comprised of a core section made up of a plurality of filaments, a web wrapper around the periphery of the core filaments, the filter being characterized in that the wrapper is comprised of a sheet material which carries a heat-sensitive coating having been activated so as to bond the periphery filaments of the core section to the wrapper whereby any tendency of smoke to pass through the filter to by-pass between the Wrapper and the core filaments is minimized.

10. A product in accordance with claim 9 wherein the coating contains a coloring material so that there is imparted a tinted eflect to the wrapper when the filter is viewed from the outside.

11. A product in accordance with claim 9 wherein the coating composition contains a flavoring material.

12. A tobacco smoke filter comprised of a core section made up of filaments, a paper wrapper around the periphery of the core filaments, the filter being characterized in that the inner surface of the paper wrapper adjacent the core filaments carries a coating comprising a thermoplastic cellulose ester composition.

13. A product in accordance with claim 12 wherein the thermoplastic cellulose ester composition comprises a mixture of cellulose acetate and triacetin.

14. A paper wrapper coated on one side thereof with a composition comprising cellulose acetate and triacetin adapted to be bonded substantially evenly to the outer surface of a tobacco smoke filter by the application of heat, thereby minimizing any tendency of smoke passed through the filter to by-pass between the wrapper and the filter.

(References on following page) References Cited in the file of this patent 2,813,051

UNITED STATES PATENTS 856,030 Cavargna June 4, 1907 2,916,038 2,175,125 Mack et a1 Oct. 3, 1939 5 2,476,582 Browne et a1. July 19, 1949 2,484,003 Simison Oct. 4, 1949 121 414 2,688,380 MacHenry Sept. 7, 1954 8 MacI-Ienry Nov. 12, 1957 Touey Apr. 14, 1959 Schur Sept. 22, 1959 Wade Dec. 8, 1959 FOREIGN PATENTS Australia May 16, 1946 

1. A NON-BY-PASSING TOBACCO SMOKE FILTER COMPRISED OF A CORE SECTION MADE UP OF CRIMPED, CONTINUES THERMOPLASTIC FILAMENTS JOINED AT RANDOM POINTS OF CONTACT, A PAPER WRAPPING MATERIAL AROUND THE PERIPHERY OF THE CORE, THE FILTER BEING CHARACTERIZED IN THAT THE WRAPPER CARRIES ON A SUBSTANTIAL PORTION OF THE SURFACE ADJACENT THE CORE A HEAT-SENSITIVE COATING COMPOSITION WHICH IS BONDED TO A SUBSTANTIAL PORTION OF THE PERIPHERY CORE FILAMENTS WHEREBY ANY TENDENCY OF SMOKE PASSED THROUGH THE FILTER TO BY-PASS BETWEEN THE WRAPPER AND THE CORE FILAMENTS IS THEREBY MINIMIZED. 